Switching amplifiers, including switched mode power amplifiers (SMPA), are known. One type of switching amplifier is a “Class E” amplifier, which is a highly efficient switching power amplifier. FIG. 1 shows a prior art single-ended Class E power amplifier. Use of a Class-E power amplifier is described in “Class E, a new class of high-efficiency tuned single-ended power amplifiers” (IEEE Journal Solid State Circuits, Vol SC-10, June 1975, pages 168 to 176)
Use of a Class E power amplifier is described in “An LDMOS VHF Class-E Power Amplifier Using a High-Q Novel Variable Inductor” (IEEE Transactions on Microwave Theory and Techniques, Vol. 47, No. 12, December 1999, pages 2534 to 2538). In this paper, a concept of the output network and the usage of the newly developed silicon LDMOS device make it possible to achieve a record-high output power of 54 W with a comparatively high efficiency of 70% at a frequency of 144 MHz.
Further uses of Class E power amplifiers are disclosed in “Analytical Design Equations for Class-E Power Amplifiers” (IEEE Transactions on Circuits and Systems-I: Regular Papers, Vol. 54, No. 12, December 2007, pages 2706 to 2717). This paper presents an analytical solution for the ideal Class-E PA, showing the relation between the circuit elements and the input parameters. The solution reveals the existence of infinitely many design equations for the ideal Class-E PA due to freedom in the value of the DC-feed inductor and in the switch duty-cycle. Based on the analytical solution a coherent, non-iterative, procedure for choosing the circuit design elements is presented.
The listing or discussion of a prior-published document or any background in this specification should not necessarily be taken as an acknowledgement that the document or background is part of the state of the art or is common general knowledge.